The C Terminus of the Immunophilin PASTICCINO1 Is Required for Plant Development and for Interaction with a NAC-like Transcription Factor

Cybelle Smyczynski,François Roudier,Lionel Gissot,Emilie Vaillant,Olivier Grandjean,Halima Morin,Thimoté Masson,Yannick Bellec,Danny Geelen,Jean-Denis Faure

doi:10.1074/jbc.m601815200

Abstract

PASTICCINO1 (PAS1) is a high molecular weight FK506-binding protein (FKBP) involved in the control of cell proliferation and differentiation during plant development. Mutations in the C-terminal region of PAS1 result in severe developmental defects. We show here that the C-terminal domain of PAS1 controls the subcellular distribution of this protein. We also demonstrated in vitro and in vivo, by Forster resonance energy transfer, that this C-terminal region is required for interaction with FAN (FKBP-associated NAC), a new member of the plant-specific family of NAC transcription factors. PAS1 and FAN are translocated into the nucleus upon auxin treatment in plant seedlings. The nuclear translocation of PAS1 is dependent on the presence of the C terminus of the protein. Finally, we showed that FAN is involved in PAS1-regulated processes because FAN overproduction partly complemented the pas1 phenotype. We suggest that PAS1 regulates the function of this NAC-like transcription factor by controlling its targeting to the nucleus upon plant cell division.

Highlights

FKBP12 inactivation leads to severe developmental alterations and pronounced cardiac defects associated with changes in calcium flux regulation (8)
As the C-terminal region of PAS1 was required for the function of the protein, we investigated whether this region played an important role in controlling the subcellular distribution of the protein
During the exponential growth phase, during which NAC transcription factors were named after the no apical cells were actively dividing, PAS1:GFP was occasionally meristem (NAM) protein of petunia (33), and the Arabidopsis detected in the nucleus (Fig. 2C, middle, arrowheads)

Summary

Introduction

This protein was correctly produced (as indicated by GFP fluorescence) but did not complement the pas1-3 mutant, demonstrating the functional importance of this C-terminal domain. During the exponential growth phase, during which NAC transcription factors were named after the no apical cells were actively dividing, PAS1:GFP was occasionally meristem (NAM) protein of petunia (33), and the Arabidopsis detected in the nucleus (Fig. 2C, middle, arrowheads). We evaluated FRET efficiency by a method based on an increase in donor fluorescence after photochemical destruction of the acceptor in N. benthamiana leaf cells coexpressing the PAS1:GFP and DsRED:FAN constructs (Fig. 3E).

Results

Conclusion